I have no idea who or what "Manon" is. For a long time I gave her no name, simply referring to her as "She" or (in print) ">She<", the angled brackets meant to convey the impression of wings, because I connected Manon in my mind with flight and visions of Asriel and Chara together as they _should_ have been, fused out of love and freedom and not out of desperation to escape a trap, soaring together around Mt. Ebott. I still have that image in my mind, although it's shifted and changed too.
My ex., K., did not like this development. She claimed that Manon was a "guilt elemental". I've never understood this.